navigate · Tanstack Start Devtools MCP: Risk & Policy

WHAT IT DOES

What navigate does on Tanstack Start Devtools

AI agents invoke navigate to trigger actions in Tanstack Start Devtools. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why navigate needs a policy

Navigation is an executable action that causes side effects in the browser environment. While not destructive or financial, it represents code/operation execution where the outcome depends on agent-provided arguments. An agent could navigate to malicious URLs, trigger unintended page loads, or cause state changes.

From the tool's definition Tool description states it 'Asks the connected browser app to navigate to an href' — this is a browser action that triggers external operations (navigation) whose effects depend on the href argument provided by the agent.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

navigate Rate-limited

navigate stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "navigate": {
      "limits": [
        {
          "counter": "navigate_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Tanstack Start Devtools, so you can run agents against it safely.

FAQ

Questions about navigate

What does the navigate tool do? +

Asks the connected browser app to navigate to an href. It is categorised as a Execute tool in the Tanstack Start Devtools MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on navigate? +

Register the Tanstack Start Devtools MCP server in PolicyLayer and add a rule for navigate: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Tanstack Start Devtools. Nothing to install.

What risk level is navigate? +

navigate is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit navigate? +

Yes. Add a rate_limit block to the navigate rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block navigate completely? +

Set action: deny in the PolicyLayer policy for navigate. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides navigate? +

navigate is provided by the Tanstack Start Devtools MCP server (mantrakp04/tanstack-start-dev-tool-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.